Calculator mechanism



Oct. 19, 1948. F. TELL-ANDER, JR

CALCULATOR MECHANISMS 2 Sheets-Sheet 1 Filed June 13, 1947 Oct. 19, 1948. TELLANDER; JR v 2,451,784-

CALCULATOR MECHANI SM S Filed June 15, 1947 2 Sheets-Sheet 2 Patented Oct. 19, 1948 UNITED STATES PATENT OFFICE CAI JCULATOR MECHANISM Frederic Tellander, Jr., Sheldon, 111., assignor to Victor 0. Lothman, Evanston, 111.

Application June 13, 1947, Serial No. 754,503

8 Claims. 1

The present invention relates to calculating machines, and more particularly to a relatively simple, inexpensive, and yet accurate manually operative device.

Various types of calculating machines have appeared on the market, but the majority of them are rather complicated and require considerable skill in operation. The simpler devices generally have had the disadvantage of being more or less inaccurate. While a slide rule is a relatively simple device from a mechanical construction viewpoint, it is limited to approximate calculation and requires some instruction and study. There are many times in almost every business where it would be desirable to have a relatively simple yet accurate device which is capable of handling the problems of multiplication, division, and the obtaining of percentages. Of course, it is possible to provide individual slide rules or calculators for the various special situations arising in business, but in the interest of economy it would be desirable to provide a calculating machine or device which is readily adaptable to specialized uses.

In accordance with the present invention, it is possible to provide a relatively simple and inexpensive calculating machine or device which employs the principle of logarithms. and thereby make available a device which is sufficiently accurate for the great majority of the calculations to be performed in connection with various business situations.

In accordance with the present invention, it is contemplated to employ a plurality of calibrated tapes which are so controlled with respect to one another that a point on the tape in cooperation with a hair line always represents a mathematical equation. In a preferred form, three tapes are employed, two of which are movable relative to each other so that the third tape displays the answer. Special tapes may be provided for special calculations, but the mechanism employed is the same in all instances.

It, therefore, is an object of the present invention to provide in a simple calculating machine the means for moving in coordinated manner relative to each other a plurality of positively driven tapes.

Another object of the present invention is to provide positive driving means for two driven members either one of which is movable relatively to a third driven member.

Still another object of the present invention is to provide in a calculating machine positive clutching means for engaging collectively either of two driven members.

' Still another object of the present invention is to provide in a calculating machine clutching and shifting means for connecting a driving Shaft to either one of two driven members.

Still another object of the present invention is to provide in a calculating machine positive braking means cooperating with clutch means for sequentially or concomitantly braking a driven member while releasing the driving clutch therefor.

Other and further objects of the present invention subsequently will become apparent by reference to the following description taken in conjunction with the accompanying drawings wherein:

Figure 1 is a side view of the present invention with the cover shown in cross-section and one element of the present device partially broken away;

Figure 2 is a plan view of the device as seen in the direction of the arrows along the stepped line 22 of Figure 1;

Figure 3 is a transverse cross-sectional view as seen in the direction of the arrows along the stepped line 33 of Figure 2 Figure 4 is a cross-sectional view along the driving element of the device as seen in the direction of the arrows along the line 4-4 of Figure 3;

Figure 5 is an end view showing one of the brake and clutch discs employed in the device illustrated in Figure 4;

Figures 6, 7, 8, 9 and 10, illustrate the progressive movement of the shifting lever from its leftward position shown in Figure 4 to that shown in Figure 11; and Figure 11 illustrates the relationship of certain elements when the shifting lever of the calculator has been moved into its rightward position.

Referring more particularly to the Figures 1, 2 and 3, of the drawing it will be seen that the present construction of the invention is provided with a base 2| which has a cover -22 having at its top three windows or apertures 23, 2d and 25. On the side the cover is provided with an aperture 26 through which a shifting button 2] projects from the mechanism within the cover.

Within the cover 22 there'is provided a frame comprising a pair of upright members 28 and 29 which may be secured to the base 2i by means of screws 3|. The upright members 28 and 29 are interconnected by bracket 32 which carries a rod 33. Mounted on the bracket 32 are a pair of parallel upright brackets 34 each having apertures through which the rod 33 extends. Between the two brackets 36 there is mounted a toroidal spring 35.

Mounted on the rod is a sleeve 36 having a conical enlargement 31. The sleeve 36 is connected to a shifting lever and fork 38 having bifurcated extremities 39 as seen in Figure 3. The shifting button 21 is mounted on the lever and fork 38. The lever 38 may be moved from the position shown in Figure 2 to the dotted line position shown from which it will become apparent that the conical enlargement 31 passes through the toroidal spring 35 and that the spring acts as a means for urging the lever 38 in either of two positions. Thus means are provided for insuring that the shifting lever 38 cannot be left in an intermediate position. While this particular means has been shown in the drawing for accomplishing this result, it is to be understood that any other suitable means may be. employed. I

The frames comprising the upright brackets 28 and 29 also carry a shaft 4| which has mounted thereon a plurality of drum 42, 43 and 44. These drums 42, 43 and 44 carry tapes 45, 46 and 4'! having indicia thereon which appear in the window openings 23, 24 and '25 respectively. The drums 42, 43 and 44 are mounted so as to rotate freel on the shaft 4| and hence are merely idler drums serving to hold the tapes adjacent to the observation windows. The ends of the 'tapes 45, 46 and 47 are contained within cylindrical storage compartments 43 and 49 which rest upon the base 2|. I

The frames 28 and 29 also carry a driving shaft to which is secured a driving knob or wheel 52. Mounted on the shaft 5| directly beneath the drums 42, 43 and 44 are sprocket drums 53, 54 and The latter drum 55 is fixedly secured to the shaft 5| whereas the other drums are so arranged that by means of a suitable mechanism they may be moved into and out of driving relation with respect to the shaft 5!.

By referring more particularly to Figure 4 it will be noted that the drum 55 is secured to the shaft 5| by means of a set screw 56 or some other suitable fastening means.

Mounted on the shaft 5| is a sleeve 51 which carries the drums 53 and 54. The ends of the sleeve 51 are provided with notches 58 and 59 for cooperation with pins 6| and 62 which are secured transversely of the shaft 5|. The notched ends 58 and 59 of the sleeve 5'! are so arranged that the sleeve is reciprocable on the rod or shaft 5| for a certain distance. The sleeve 51 at its intermediate portion is provided with oppositely arranged notches or cut-away portions 63, 64, 65 and 56, respectively. Occupying the notch 63 and on the shaft 5| there'is a clutch disc 61 having a friction surface 68 adapted to bear against the recessed end portion 69 of the drum 53. .The disc Bl is engaged by a spring which bears against a collar H' which is mounted within the notch 64. A similar arrangement of elements is provided for the drum 54..

The drum 54 is provided with a recessed end l2 within which is mounted a clutch disc 13 occupying the notch 65 and carrying a. friction surface 14. The clutch disc 13 is engaged by a spring bearing against a collar 16 which is mounted in the notch 65. The fork 38 having a bifurcated ends 39 is adapted to engage either the collar H or the collar 16 in order to bring about disengagement or engagement of the clutch surfaces with the different sprocket drums.

When the drum 53 is in driving relationship to the shaft 5| by virtue of arrangement of the parts in the position shown in Figure '4 it is desired to hold the other drum 54 in a fixed position. This is accomplished by the provision of a brake disc I! having a friction surface '18. The brake disc such as shown in Figure 5 has a notch 19 for accommodating a rod or bar 3| which is se- 8| prevents the brake disc 11 from rotating. The

4 brake disc 11 is engaged by a spring 82 bearing against the end support plate 29.

The brake disc for the drum 53 which comprises the disc 84 and the friction surface 85 is similar to the disc shown in Figure 5. The clutch discs for both the drums comprising the disc 61 and friction surface 68 and the disc 13 and the friction surface 14 are also similar in construction to the disc shown in Figure 5. The notches 79 however cooperate with the notches 63 and 66 of the sleeve 51 and the sides of the notches 19 fit about the rod or shaft 5|. These notches 53 and 66 prevent the clutch discs from being displaced angularly relative to the rod 5| while permitting limited longitudinal movement relative thereto.

When the drum 54 is in driving relation with respect to the shaft 5| it is desired to hold the other drum 53 fixed. Accordingly, the other support bracket 28 is engaged by a spring 83 which bears against a brake disc '84 having a friction surface 85. The brake disc 84 is kept from rotating by a horizontal bar 86 carried by the vertical support28.

The drum 54 is prevented from moving to the right by a washer which engages the pin Bi, and similarly the drum '53 is kept from moving to the left by a washer which engages the pin 52. The springs of the clutch mechanism substantially prevent each drum from moving in the opposite direction, but to insure that neither drum will move longitudinall any appreciable amount during a clutch shifting operation there is provided the member which is carried by the frame 32 or mounted on thebase 2|.

Thearrangement of components shown and illustrated in Figure 4 constitute a clutch and brake arrangement providing certain concomitant or sequential operations whereby the brake is applied to a driven drum before that drum is released from engagement with its driving clutch and the driving clutch of the other drum is engaged with it prior to the time that its brake is released. Due to the snap action of the toroidal spring 35 cooperating with the conical enlargement 3'! of the sleeve 36 the operations performed are substantially concomitant. The manner in which this operation takes place is illustrated by the posit-ions of the various parts in Figures 6 to 11 inclusive. In Figure 4 the brake for the drum 53 is disengaged therefrom and the drum is in engagement .with its driving clutch. The drum 54 is held in fixed position by its brake. It now may be assumed that pressure has been applied to the operating button 21 which moves clutch fork 38 from left to right. The initial movement of the fork 38 is illustrated in Figure 6 which shows that the spring 15 expands. At the same time the brake spring '83 also expands so that the brake disc 84 engages the drum 53 and also bears against the end of the sleeve 5'! and shifts the sleeve toward the right. The movement of the sleeve 51 toward the right produces a movement of the collar '16 thus resulting in a movement of the clutch disc '63 so that the clutch surface 14 is in light engagement with the recessed surface 12 of'the drum 54. The movement of the sleeve 51 however, is not yet sufiicient to take up the clearance between the other end of the sleeve and the brake disc Ti.

Figures 7 and 8 show the relationship of the shifting fork or lever '38 with respect to the collars ll andlE during that portion of the time when the conical enlargement '31 of the sleeve 36 is passing through the toroidal spring 35' From these two figures and from Figure 9 it will be noted that for a considerable interval the fork 38 is being contacted by both of the collars or plates ii and i6. Snap action provided by the toroidal spring 35 insures movement of the fork 38 to the positions shown in Figures 10 and 11.

In Figure 10 it will be noted that the shifting lever or fork 38 is no longer in engagement with the plate H and hence the clutch disc 61 is no longer in engagement with the drum 53. From Figure 9 it will be noted that in that position the right end of the sleeve 51 has taken up the clearance between the sleeve and the brake disc 11 on .the drum 54. Further movement toward the right of the sleeve 5'! therefore moves the braking disc l'l away from the drum 54 so that the brake eventually reaches the position shown in Figure 11. In that figure it is apparent that drum 53 still is held rigidly in position by its brake .while drum 54 has been placed in driving relationship with the shaft 5|.

The foregoing mode of operation has been provided to insure the proper relationship between the strips which are driven by the various drums 53, 54 and 55. In order .that the tape driven by the third drum shall accurately display the answer in the Window it is necessary that the drum 55 always moves whenever there is any movement of either of the drums 53 or 54 while the other of these drums is held stationary by its brake.

If, for example, it is desired .to multiply, either the multiplier or the multiplicand is set up on the tape exhibited in wind-ow 23 and driven by the drum 53. When the proper number has been brought under the hairline of window 23 the lever 38 is moved from the position shown in Figure 4 to that illustrated in Figure 11 whereupon the other number is thereupon made to appear at the hairline in window 24. When this has been accomplished the product may be read at the hairline in window 25.

If it is desired to divide one number by another the dividend may be set up in window 23 and the divisor may be set up in window 25 whereupon the quotient will appear in window 24. In either operation there is no difficulty encountered in determining where to place the decimal point as is the case when slide rule or other calculators are employed. The use of tapes also makes it possible to attain a much greater degree of accuracy since there is not the space limitation which is imposed upon the construction of a slide rule or upon other mechanical arrangements employing belts or drums. In one embodiment, tapes of 100 inche in length were employed thus providing an accuracy to four significant figures which is sufficient for most commercial percentage calculations.

By providing different sets of tapes for the device constructed in accordance with the present invention it is possible to make such other calculations as: wage calculations, invoice extensions, interest computations, prorations of expenses and costs, and percentage calculations of all types. To facilitate s-uch computations thewindows or openings of the casings which are each provided with a cross-hair may be appropriately labelled. Thus, for example, the lefthand window may be marked Time worked, the center window, Hourly rate, and the third or righ'thand window, Amount of wages. The Time worked tape could be calibrated in hours and minutes so that the total amount may readily be obtainedwithout consideration of the location of the decimal point as is the case in many other calculators and slide rules. The third or righthand window can further be divided into a plurality of col-- umns so as to provide the total amount due for straight time, time and one-half, and double time.

A further example of the manner in which the windows and the cooperating tapes may be employed is where the lefthand window carries the notation, Quantity, the center window Price and the righthand window Extension. The first tape would show all common fractions which are the usual source of difliculty on most calculators. Thus there is no need of converting the fractions to decimal equivalents. Similarly, the relationship between cost and retail price may be obtained by having the first window indicate the cost. the center window the retail price, and the third or righ't'hand window the per cent markup. Likewise, the righthand window may be em- .ployed with two columns on the tape so as to provide a comparison of increase or decrease in percentage with respect to two different sets of costs to be indicated on the first two windows.

The foregoing illustrations are merely given as examples of a few of the calculations commonly encountered. By suitable tapes it is possible to provide convenient calculations for winding transformers, obtaining the inductance in coils, calculatin the resonant frequencies, obtaining variations in proportions for chemical formulas, as well as the more common calculations ordinarily obtained through the use of slide rules including square root, cube root, sines, tangents, logarithms and other factors.

While for the purpose of illustrating and describing the present invention, a preferred embodiment has been shown in the drawings, it is to be understood that the invention is not to be limited thereby since such variations in the components and in their arrangement are contemplated as may be commensurate with the spirit and scope of the invention set forth in the following claims.

What I desire to protect by United States Letters Patent is claimed as follows:

1. The combination in a calculator having a plurality of rotatable members, a drive shaft for said rotatable members, a frame for said shaft, a spring biased brake for each of said members, said spring biased brakes being arranged to en age said frame and normally to engage said rotatable members, a brake releasing member mounted on said drive shaft, a pair of clutches for interconnecting either of said members with said drive shaft, and an over-center shifting means for controlling said clutches, said brake releasing member being responsive to the action of said clutches to disengage a brake from one of said members.

2. The combination in a calculator having a plurality of indicia bearing means arranged movable relative to each other, comprising a frame, a drive shaft mounted in said frame, a, plurality of clutches associated with said drive shaft, a plurality of driven members for driving said indicia bearing means, a spring biased brake mounted between said frame and one of said driven members, a second spring biased brake mounted between said frame and the other of said driven members, a brake releasing sleeve surrounding said drive shaft, :3. pair of clutches arranged for selective engagement to interconnect either of said driven members with said drive shaft, said clutches being arranged to produce action of said 7 brake .releasmgsleeve, and a snap action shifting means for controlling said clutches.

'3. The combination .in a calculator having a 'pluralityof perforated :tapesbearing indicia comprising a plurality of driven sprocket members for said tapes, a drive shaft for said sprocket members, a frame for said, drive shaft, a spring biased :brake for each :of :said sprocket members, said :brake being mounted in engagement with said frame and surrounding said driveshaft, a sleeve mounted on said drive shaft for releasing saidspring biased brakesgone at a time, :apair of clutches arranged for interconnecting said drive shaft with said sprocket zmembers, means associated with said-clutches for actuatingsaid brake releasing member, and snap action .means for shifting said clutches.

4. Ina calculator, the combinationcomprising a plurality of sprocket members for driving a plurality of perforated tapes .having indicia thereon and bearing .a certain mathematical relation to each other, a drive shaft for said sprocket members, a frame forsaid drive shaft, a clutch mechanism for each sprocket member, a brake'for each sprocket member, said brake being spring biased for normal engagement with its associated sprocket member, a sleeve mounted on said drive shaft for axial movement relative thereto, said sleeve being arranged to disengage one brake at a time from its associatedsprocket member, said sleeve being provided with means responsive to a predetermined amount of movement of said clutch mechanism, and asnap action clutch shifting means for disengaging one of said clutches from its sprocket member and for causing the other of said clutches to engage its sprocket member.

5. vIn a calculator having a plurality of tapes bearing indicia thereon and having a certain mathematical relation to each other, the combination comprising a frame, a drive shaft mounted in said frame, a reciprocable sleeve mounted on said shaft, a plurality of drums mounted for rotation on said sleeve and being arranged to drive said plurality of tapes, a clutch mechanism for each drum, each clutch having a collar arranged to engage said sleeve whenever said collar has moved beyond .a certain point, an over-center shifting means for engaging said collar to change the driving connection between said drums and said drive shaft, a'br-ake for each drum arranged normally to engage its associated drum, said brakes being arranged to be disengaged by said reciprocable sleeveso as to cause the application of a 'brake'to a drumprior to the time that the other brake is released from the other drum.

6. A calculator having a plurality of movable perforated tapes comprising a frame, a drive shaft mounted therein, a plurality of sprocket members for driving said tapes, a spring biased brake interposed between each sprocket member and said frame, a reciprocable sleeve mounted on said shaft for Qdisengaging one :br-ake ata time from its sprocket :member, said sleeve in one .posi- ,tion being :out of engagement with either brake, a plurality of clutch members mounted on said shaft for driving said sprocket members, each clutch member having a spring and acollar, said collar beingarranged to actuate said sleeve whenever said collar moves beyond a predetermined .amount, and:means for engaging said collars to cause said clutches to engage .and disengage said sprocket members.

7. In .a calculator having a plurality of movable ;perforated tapes, the combination comprising aframe, a drive shaft carried thereby, a plurality of tape driving members, a spring biased brake interposed between each driving member and said frame, a reciprocable sleeve mounted on said shaft for disengaging one brake at a time from its associated driving member, said sleeve having a plurality of spaced apart stop members, said sleeve in one position being out of engagement with either brake, a plurality of clutch members mounted adjacent said shaft for driving said driving members, each clutch member having a biasing spring and a collar, said collar being arranged to engage a stop member to actuate said sleeve whenever said collar moves in excess of a predetermined amount, and ashifting lever for engaging said collars to cause said clutches to engage and disengage said driving members.

8. In a calculator having a plurality of movable perforated tapes, the combination comprising a frame, a drive shaft carried thereby, a plurality of tape driving members arrangedin axial alignment on said shaft, a spring biased brake interposed between each driving member and said frame, a reciprocable sleeve mounted on said shaft for disengaging one .brake at a time from its associated driving member, said sleeve having a plurality of spaced apart notched stop members, said sleeve normally being out of engagement with one-of said brakes andbeing capable of being moved transitionally-out of engagement with both of said brakes, a plurality of clutch members mounted co-axially relative to said shaft for driving said driving members, each clutch member having a spring and a collar, said collar-being arranged to engage .said notched stop of said sleeve whenever said collar moves in excess of a predetermined amount, and a shifting lever for engaging said collars to cause said clutches to disengage and engage said driving members.

.FREDERIC TELLANDER, JR.

No references cited. 

